This invention relates to a method of and apparatus for automatically sorting articles and more particularly to a method and apparatus for automatically sorting articles such as harvested fruit and vegetable crops in accordance with their shape, size and the presence and seriousness of defects.
It has been conventional practice when sorting such articles to establish the grades required and the criteria for each grade in advance of the sorting operation and then for workers to manually randomly sort produce in accordance with the pre-determined grades. The disadvantage of such a system is that it is necessarily labour intensive and accordingly costly.
An object of the present invention is to provide improvements in relation to one or more matters discussed herein and/or generally.
According to the invention there is provided apparatus for grading articles such as fruit and vegetables, and a method of grading articles such as fruit and vegetables as defined in the accompanying claims.
In an embodiment of the invention apparatus for inspecting and sorting articles such as fruit and vegetables comprises a spool or roller conveyor onto which articles are presented from a discharge chute. The discharge chute may oscillate to assist alignment and movement of the articles discharged onto the conveyor. The conveyor carries the objects under a viewing device or inspection zone at which a camera-type scanning unit is mounted overhead of the conveyor in such a way that the camera can scan the articles as they pass underneath. The roller elements of the conveyor are driven to rotate during the scanning process in order that the articles thereon also rotate to afford as full a view as possible of the articles.
Apparatus such as a video grabber converts the visual image data provided by the camera. This information is passed to a central processing unit which analyses and evaluates the images of the individual article created by the camera as to size (length/diameter/volume), grade (rot, cracks, damage etc) and orientation as well as position in the direction of travel and the space occupied on the conveyor as the article sits in the valleys formed between successive roller elements. Any defects present are characterised into groups in accordance with pre-determined characteristics and converted into a numerical value, such as a percentage. An operator establishes, by means of a set-up screen, the required characteristics or numerical value of the particular grade to be selected for. The operator controlled program then establishes a discharge position where selected articles will be removed from the conveyor according to the required classification, that is by size, grade or direction of orientation. The central processing unit would determine the point at which the selected article is to be removed and how many actuators to activate to cause article removal devices or flip levers located just under the full length of the product to flip the article onto the take out conveyor or flume.
Tracking means mazy ho provided on the conveyor so as to enable the position of each article to be followed, thus facilitating removal of the particular article from the conveyor on reaching the required discharge position.
Articles may be removed or ejected from the conveyor at the required position by article removal devices. A plurality of devices may be provided and mounted at intervals between the roller elements and across the width of the conveyor. The devices comprise a flip lever.
In another embodiment of the invention said article removal elements may be in the form of projections. Said projections may be of finger-like form. The finger-like projections may be inclined forwardly with respect to their direction of angular movement when actuated.
In a further embodiment of the invention the flip levers may be shaped, for example, diablo shaped, to suit the particular type of articles being graded such as citrus fruits.
The flip lever may be pivotally mounted beneath the conveyor. Each flip lever, when activated, moves in an upward direction and passes between two successive pairs of roller elements to contact an article lying on the conveyor. The upward momentum imparted to the article as a result of contact between the flip lever combined with the forward momentum from the roller conveyor causes the article to be carried upwardly, or xe2x80x9cflippedxe2x80x9d onto a discharge belt or flume while the flip lever retracts.
Transverse overhead take-out conveyors or water flumes are provided to collect and deliver to the side of the machine those articles which are removed from the conveyor when the required position is reached. The articles are flipped up and into the take-out conveyor or flume by the flip levers in the roller conveyor system.
In an embodiment two or more article removal devices such as flip levers may be provided for each article to be removed, wherein the size of the article may determine the number and/or sequence of elements which are actuated at any one time.
Those articles remaining on the conveyor will be discharged over the end of said conveyor. In most cases these articles will represent the prime grade required.
Any number of discharge belts and corresponding ejector mechanisms may be provided depending on the number of classifications required during a given. operation.
A typical machine will have three take-out positions with the required ejector mechanisms and discharge belts in addition to the over the end separation point making a total of four although any number of take-out points may be provided, It is envisaged that the take-out points will be of modular construction and the length of the machine may be extended by adding further such points. It is also envisaged that the apparatus herein before described will replace the conventional inspection conveyor normally positioned between the station for washing/sorting of articles and packing which is generally manned by a number of people.
According to the invention there is also provided a method for inspecting and sorting articles such as fruit and vegetables, said method comprising the step of locating the articles on a conveyor for example by discharging the articles from a chute onto a spool or roller conveyor. The chute may be caused to oscillate to assist alignment of the articles. The articles on the conveyor pass under a viewing device or inspection zone at which the articles are inspected and scanned as they pass. The method comprises the step of analysing an image or other data from each article by a data processing and control system, said data being processed in order to classify the articles according to shape and/or size and/or defects. The method comprises the step of causing a selection of said classified articles to be removed or ejected from the conveyor in response to said classification. During the step of removal or ejection, the article is caused to be lifted from the surface of the conveyor and moved to a discharge conveyor.
An advantage of the invention described herein is that it provides a faster, less labour intensive and accordingly a more economical method for sorting articles such as fruit and vegetables.